Studies have indicated the particular persistence and severity of early-onset obesity, and the probable effect of early nutritional level on the number of fat cells developed. Schacter's work and Rodin's subsequent research have led to a notion of increased sensitivity to external stimulation in the obese adult, which extends beyond simple food-cue related behaviors. It is important to learn whether this stimulus sensitivity seen in the obese adult functions from birth, and to what extent it may affect early eating behavior and the development of the parent-child feeding interaction. The aim of the research is to assess individual differences in the newborn human infant's sensitivity to stimuli in the modalities of vision (using techniques of infra-red video-recording of corneal reflection), and taste (using a nipple system allowing controlled delivery of fluids and monitoring the components of the sucking response). These initial differences measured within several days of birth will be related to variation in measures of parental stimulus sensitivity and measures of parental, newborn, and infantile adiposity. Further, in the longitudinal design, the stability of differences observed initially will be assessed over a somewhat longer period (three months) of infantile development in a total of three observations. Finally, it is our hope to relate these differences in stimulus sensitivity to differences in eating behavior at birth and in the development of feeding interactions as determined from home observations during early infancy.